Health risk assessment of typical metalloid and heavy metals in rural drinking water in Shaanxi Province in 2020

Abstract

Evaluate the health risks of metalloid and heavy metals in rural drinking water in Shaanxi Province, and provide a scientific basis for ensuring the safety of drinking water for rural residents. In 2020, the rural drinking water in Shaanxi Province were monitored, referring to the "Sanitary Standards for Drinking Water"(GB 5749-2006) for arsenic(As), cadmium(Cd), chromium(Cr~(6+)), lead(Pb), and mercury(Hg) in the water. To evaluate the concentration of five metalloid and heavy metals, the health risk assessment method recommended by United States Environmental Protection Agency was used to evaluate the health risks of adults in rural areas exposed to metalloid and heavy metals through drinking water. In 2020, a total of 6232 water samples were monitored. The concentrations of Cd, Pb and Hg in the water all met the standards, and the compliance rates of As and Cr~(6+) were 99.98% and 98.09%, respectively. The carcinogenic risk level of As was 3.53×10~(-5), and the non-carcinogenic health risk levels of the four heavy metals in descending order were Pb>Cr~(6+)>Cd>Hg, and the total risk level was 0.105. The concentration level of As and the distribution of health risk levels were all in northern Shaanxi>Guanzhong region>southern Shaanxi(P<0.05). The concentration level and health risk level distribution of As and Cr~(6+) were all groundwater>surface water(P<0.05), and the concentration level and health risk level distribution of Cd, Pb and Hg were all surface water>groundwater(P<0.05). There was a potential health risk of As exposure in rural drinking water in Shaanxi Province in 2020. The non-carcinogenic health risks of four heavy metals intake of Cd, Hg, Pb and Cr~(6+) through drinking water were still at an acceptable level. The control of arsenic pollution in drinking water should be further strengthened to ensure drinking water safety.